Albert Barnes Commentary Isaiah 57:20

"But the wicked are like the troubled sea; for it cannot rest, and its waters cast up mire and dirt." — Isaiah 57:20 (ASV)

But the wicked - All who are transgressors of the law and who remain unpardoned. The design of this is to contrast their condition with that of those who should enjoy peace. The proposition is, therefore, of the most general character. All the wicked are like the troubled sea. Whether prosperous or otherwise; rich or poor; bond or free; old or young; whether in Christian, in civilized, or in uncivilized lands; whether living in palaces, in caves, or in tents; whether in the splendor of cities, or in the solitude of deserts; All are like the troubled sea.

Are like the troubled sea - The agitated (נגרשׁ nigrâsh), ever-moving and restless sea. The sea is always in motion, and never entirely calm. Often also it lashes into foam, and heaves with wild commotion.

When it cannot rest - Lowth renders this, ‘For it never can be at rest.’ The Hebrew is stronger than our translation. It means that there is no possibility of its being at rest; it is unable to be still (כִּי הַשְׁקֵט לֹא יוּכָל kı̂y hash^eqēṭ lo' yûkal). The Septuagint renders it, ‘But the wicked are tossed like waves (κλυδωνισθήσονται kludōnisthēsontai), and are not able to be at rest.’ The idea, it seems to me, is not precisely what our translation appears to convey—that the wicked are like the sea, occasionally agitated by a storm and driven by wild commotion. Rather, the idea is that, like the ocean, there is never any peace for them, just as there is no peace for the restless waters of the mighty deep.

Whose waters - Those who have stood on the shores of the ocean and seen the waves—especially in a storm—foam, and roll, and dash on the beach, will be able to appreciate the force of this beautiful figure, and cannot help but have a vivid image before them of the unsettled and agitated hearts of the guilty. The figure which is used here to denote the lack of peace in the heart of a wicked person, is likewise beautifully employed by Ovid:

Cumque sit hibernis agitatum fluctibus aequor,
Pectora sunt ipso turbidiora mari.

Trist. i. x. 33

The agitation and commotion of the sinner referred to here relates to such things as the following:

1. There is no permanent happiness or enjoyment. There is no calmness of soul in contemplating the divine perfections and the glories of the future world. Wealth, business, pleasure, and the pride, pomp, and flattery of the world provide no substantial and permanent peace. All these things leave the soul unsatisfied or dissatisfied; they leave it unprotected against the rebukes of conscience and the fear of hell.
2. Raging passions. The sinner is under the influence of raging passions, which may be compared to the wild and tumultuous waves of the ocean. Thus, the hearts of the wicked are agitated with conflicting passions such as pride, envy, malice, lust, ambition, and revenge. These leave no peace in the soul; they make peace impossible. People may learn to control them to some degree through philosophy, or pride in their character and respect for their reputation may enable them to restrain these passions to some degree. However, these passions are like the smothered fires of a volcano, or like the momentary calm of the ocean that a gust of wind may soon lash into foam. To restrain them is not to subdue them, for no one can tell how soon they may be provoked by anger, or how soon the smothered fires of lust may ignite.
3. Conscience. Nothing more resembles an agitated ocean casting up mire and dirt than a soul agitated by the recollections of past guilt. A deep dark cloud in a tempest overhangs the deep; lightning plays and thunder rolls across the sky, and the waves heave with wild commotion. So it is with the heart of the sinner. Though there may be a temporary suspension of the rebukes of conscience, there is no permanent peace. The soul cannot rest; and in some way or other, the recollections of guilt will be aroused, and the heart thrown into turbid and wild agitation.
4. The fear of judgment and of hell. Many a sinner has no rest, day or night, from the fear of future wrath. Their troubled mind looks onward, and they see nothing to anticipate but the wrath of God and the horrors of an eternal hell.

How invaluable then is religion! All these commotions are stilled by the voice of pardoning mercy, as the billows of the deep were hushed by the voice of Jesus. How much do we owe to religion! If it had not been for this, there would have been no peace in this world. Every heart would have been agitated with tumultuous passion; every heart would have quailed with the fear of hell. How diligently should we seek the influence of religion! We all have raging passions to be subdued. We all have consciences that may be troubled with the recollections of past guilt.

We are all traveling to the bar of God and have reason to fear the storms of vengeance. We all must soon lie down on beds of death, and in all these scenes, there is nothing that can give permanent and solid peace but the religion of the Redeemer. Oh! It stills all the agitation of a troubled soul, lays every billow of tumultuous passion to rest, calms the conflicts of a guilty heart, reveals God reconciled to our souls through a Redeemer, and removes all the anticipated terrors of a bed of death and of the approach to the judgment bar. Peacefully the Christian can die—not as the troubled sinner, who leaves the world with a heart agitated like the stormy ocean, but as peacefully as the gentle ripple dies away on the beach.

How blessed the righteous when they die,
When holy souls retire to rest!
How mildly beams the closing eye,
How gently heaves the expiring breast!
So fades a summer cloud away;
So sinks the gale when storms are over;
So gently shuts the eve of day;
So dies a wave along the shore.

- Barbauld